So after reading this question I came up with a really bad doubt.
In the past I was using quite often "(no) se hace falta" to say for instance, that "it is (not) necessary to", but I've by then been ...

Many materials for learning Spanish, discuss the "impersonal se" (e.g. ¿Se puede tocar esto?) and "passive se" (e.g. Se habla español.).
What exactly are these forms grammatically? Is the se in both ...